1. Field of the Invention
The present invention relates to a disk array apparatus and a method for controlling the disk array apparatus.
2. Description of the Related Art
The quantity of data to be processed by a computer system has been abruptly increased in these years. As a disk array apparatus for managing such a large quantity of data, there has recently come to public attention a large-scale disk array apparatus wherein a file system is coupled to a disk array apparatus of a RAID (Redundant Arrays of Inexpensive Disks) management type called mid-range class or enterprise class which offers a giant storage resource. For the purpose of efficiently using and managing such a giant amount of data, there has been developed a technique by which the disk array apparatus and an information processor are connected by means of a dedicated network (Storage Area Network, which will be referred to as the SAN, hereinafter) to realize high-speed, large-amount access to the disk array apparatus.
Meanwhile, in a related disk array apparatus, it has been common that only a disk drive having a specific type of communication interface is connected to one disk controller unit. On the recent market, however, there are available various types of disk drives which are different in their communication interface, access speed, etc., i.e., in Standard, price, etc. And from the viewpoint of the property, investment cost, etc. of a system to be operated, users' increasing need is to freely combine such disk drives to form a disk array system having a flexible arrangement. At the same time, another need is to utilize an existing disk array system more effectively by minimizing a modification in the arrangement of the existing disk array system while allowing the aforementioned flexible combination.